A desirable interface between multi-agents is through ‘over the air’ RF connections which include not only the intended direct RF communications paths but also highly variable multi-ray propagation, range attenuation, external RF influences and near earth influence. These influences are all difficult to predict, control, and repeat in an outdoor environment. This outdoor testing, as has traditionally been done, is extremely expensive while simultaneously providing less data points than more controlled events, and the testing events are generally not repeatable. A need exists for an ability to interconnect multiple devices for laboratory simulation of this outdoor environment. Currently in certain types of antenna design fields the correlation between model and simulations (M&S), hardware-in-the-loop (HITL) testing, and open air range testing has been minimal. The complexity of open air test ranges cannot be fully captured in modeling and simulation or in hardware-in-the-loop testing. Open air test ranges introduce many uncontrolled variables that not only affect the performance of an RF communications system but also impact the quality of the test data. An open air test is heavily influenced by a number of factors that other testing methods cannot completely account for, including: the ambient electromagnetic environment (EME) an RF system is operating in; the antenna placement, including the antenna's placement as compared to other antennas; the soil properties of the location being tested in; the physical terrain; the placement of the RF system within that terrain; multi-ray reflection signals; desirable signals; undesirable signals propagating in the area; hostile signals that might be trying to disrupts the RF systems functionality; general system variability; and other factors.
In open air test ranges the multiplicity of the before mentioned variables impact the quality of the data gathered from an open air test. Thus, it is difficult to determine cause and effect from open air testing because of the many variables introduced by the environment that cannot be completely accounted for with other testing methods. Furthermore, the results of the open air test are not repeatable, and the phenomenology is not clear.
Thus, a need exists to reproduce open-air near-earth effects in a lab and thereby be able to more fully utilize OAR testing. To further reproduce open-air near-earth effects a testing system needs to account for all donating competition to units under test as well as lab equipment to simulate the same. Also, a need exists to simulate an operational event with vehicle movement and controlled RF effects. Another need is to be able to reproduce the scalar effects with all of the variables for a given electromagnetic spectrum activity. Another need includes creation of a HITL laboratory environment for use in developmental test (DT) and operation test (OT) assessments as well as be able to take predictions for scalar effects from M&S and rapidly transition them into a HITL environment for validation. Another need is a requirement to converge results from M&S and OAR testing. MARPS improves RF system designs, reduces the OAR testing time, saves money in the development of future RF system technology, improves the correlation between models and system performance, increases test repeatability of real environments, and increases the ability to test new real-world complications that the RF system encounters. MARPS addresses these needs by a variety of result/effects including simulating an OAR test scenario in a laboratory using a computer, other RF equipment, and a set of digitally controlled RF paths.
An RF system being tested and used does not need modifications because the RF signals are modified by an exemplary aspect of a MARPS system rather than by modifying the generating RF devices themselves. For example, an exemplary MARPS system could be used to test a cell phone system in the presence of interfering signals where the cell phone being tested is directly plugged into the MARPS system and the interfering devices are also directly plugged into the MARPS system. Relative signal strengths are modified, not by physically moving the RF devices or by changing the signals by adjusting the generating RF device, but instead by manipulating the MARPS system paths to simulate such interactions. As a cell phone moves through an environment, signal strength of the cell phone will vary based on a multitude of variables including obstructions, other signals present, and even ground effects. A MARPS system can help create a more reliable cell phone or cell phone system by providing reproducible tests to developers without incurring the great expense of open air testing. Other examples of uses for a MARPS system would be in designing more robust police scanners, garage door openers, and other RF systems.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.